Dredge.



J. F. CRAIG. DRBDGB.

APPLIOATION FILED DEC. 26, 1913.

1,104,248. Patented July 21, 1914,

2 SHEETS-SHEET 1.

J. F. CRAIG.

7 DREDGE.

APPLIOATION FILED mm. 2a. 1913.

1 1 04,248, 1 Patented July 21, 1914.

2 SHEETS-'SHEET 2.

MW F

ms uonms'psrxns cm. WASHINGTON, a. c.

JOHN F. CRAIG, OF LONGBEACH, CALIFORNIA.

Brannon.

Specification of Letters Patent.

Patented. July 21, 1914.

Application filed December 28, 1913. Serial No. 808,652.

To all whom it may concern: Be it known that I, JOHN F. CRAIG, 3.01m-

zen of the United States, residing at Long beach, in the county of Los Angeles and State of California, have invented a new and useful Improvement in Dredges, of which the following is a s ecification.

This inventionre ates to improvements in dredges of the clam shell, dipper, or similar type, in which a boom, dipper handle. or derrick is mounted to swing horizontally, and the main object of the invention is to provide improved means, for swinging the boom in either direction in such manner as to provide for sufficient leverage or pull on the boom, with minimum obstruction to view from the operating house of the deck on which the boom is mounted. In dredges of this type the boom is generally operated by a turn table or circle, the operating cables being connected with this turn table or circle, so as to turn the same in either direction. Such turn table or circle extending directly over the supporting deck constitutes an objectionable encumbrance above the deck, it interferes with the view of the deck from the operating house, it is expensive to erect and maintaln, and very vdiflic-ult to hold in connection with the boom.

My invention provides for all the advantages presented by the turn table arrangement and particularly for the effective pull on the boom, and the capability of operation in either direction from drums secured to a single shaft which is accomplished by this arrangement, and doing away with the encumbrance of a turn table or circle and clearing the deck for convenient access of the workmen.

Another object of the invention is to provide for operation of the boom by cables operated by drums of constant diameter on a single operating shaft in such manner that there is no detrimental slack in the cables at any angle of the boom within the desired limits of swing. v

Other objects of my invention will appear hereinafter. Y

The accompanying drawings illustrate an embodiment of my invention, and referring thereto:

Figure 1 is a side elevation of a forward portion of a dredge, showing the boom and its operating means, a portion of the hull or boat being broken away. Fig. 2 1s a plan view of the parts shown inFig. 1, a portion of the suspending and operating cable being broken away to show the underlying parts. Fig. 3 1s a front elevation of the parts shown in Fig. 1, with the boom removed. Fig. at is a detail elevation of the sheave for'taking up the slack in the boom operating cables.

1 designates the dredge hull and 2 the frameor derrick, on said hull for carrying the various pulleys for the several suspending and operating cables. A boom f is mounted to swing on a pivot 5 on the deck 6 of the dredge and is supported at its outer end by the usual suspension means 8, said boom serving for support of the sheave 9 over which passes the operating cable 10 for the dredge bucket.

. The present invention relates to means for swinging the boom 4.- to one side or the other, said means comprising two cables 12 each connected at one end to a fixed support 11, and passing over the sheave or pulley 13 on the boom 4, and thence over a guide pulley 15 mounted on the frame 2,; and

thence over suitable guide pulley 16 to a winding drum 17, said winding drum being connected to. the cable to operate the same, and the respective cables 12 being wound in opposite directions on the respective winding drums 17, so that one cable is unwound while the other is wound up on its drum. The said winding drums 17 are carried by the drum shaft 18 connected to be operated by an engine 19 in the usual manner, so

that both the said drums are operated simultaneously. The outer ends of the cables are connected to a fixed support 11, preferably by means of spring connection 20 which takes up the jar when the power is thrown on the cable. A sheave or pulley 24 is pivotally mounted at 25 on the support 14 and adapted to receive the outer bight or run of the payingout cable,,and to bend such bight or-run sufliciently to take up the slack there.- in, as hereinafter described. Guard means 26 may be provided for guiding the. cable 12 into the sheave 24. Part 11 which is shown necessarily have to coincide with center of sheave 24, as shown in this cut, but: will vary where relative position of other parts shown on this drawing are changed, to accomplish the desired result.

The operation is as follows: Assuming that the boom l'stands in the position shown in full lines in Fig. 2, and that it is desired to swing it to the left,-the drum shaft18 will rotate to turn the drum 17 in such manner as to wind one cable 12 on its drum 17 and unwind the other cable 12 from its drumlY, so as to pay out the cable 12 on the right hand side and draw in the cable 12 on the left hand side. It will be noted that in this operation of the cable 12 on the left hand side the pull of the cable is always at a favorable angle to the boom '1 in respect to the pulling effect on the boom, and that as the boom swings farther toward the left the pull on this cable 12 is more and more at right angles to the boom, so that the pulling effect becomes greater the boom swings farther to that side. This is desirable for the reason that the required pull on the boom is greater in proportion to the distance the boom has swung from the center line of dredge, as the boom requires a greater pull when thrown clear over in this manner. On the other hand, the cable 12 on the right hand or paying out side tends to become more in line with the boom as the boom swings toward the left and when the boom approaches a position about in line with this cable 12 on the right hand side the motion of the right hand sheave 13 on said boom will be such that its distance from the fixed pulley 15 varies but little. The boom 4t is at this time moving directly toward the pulley 15 at the left hand side so that the portion of the left hand cable 12 between its pulleys 13 and 15 is being shortcried in full proportion to the increased length of cable 12 at right hand side. The two drums 17 being connected to operate in unison, the cable 12 at the right hand side is being paid out as fast as it is drawn in on the left hand side, and since the movement of the boom at this time is such that the pulley 13 for the right hand cable is moving in such a manner that it cannot take up all the slack created at this location on any further swing of the boom, the amount of cable paid out at the right hand side during this portion of the movement tends to produce a slack in the running cable between the pulleys 13 and 15on the right hand side. At the moment, however, that this slack tends to occur the bight or run of the cable 12 between the pulleys 13 and 15 on the right hand side swings into the sheave 24: and is thereby deflected or bent around sheave 2 1 in such manner that in the further movement of the boom the bending of the cable by this sheave in addition to the rendering of the cables around sheaves 13 serves to take up the slack which would otherwise be produced therein. By this means 1 am enabled to use the simultaneously operated drums, and yet maintain the cable taut at all times, and also provide for direct pull at the most favorable angle on the boom, and furthermore, I am enabled to accomplish these results without the use of a turn table or circle, thereby leaving the deck free and clear.

l/Vhat I claim is:

1. In a dredge, a pivot-ally mounted boom, cables connected with said boom to swing the same in opposite directions, winding drums connected with the said cables, said winding-drums being connected to operate simultaneously to pay out one cable and draw in the other cable, and means for engaging with the paying outrun of either cable, to take up slack therein.

2. In a dredge, a pivotally mounted boom, sheaves thereon, a properly located fixed support, cables connected to said fixed support and running over the respective sheaves on said boom, winding drums connected to the other ends of the respective cables, means for operating said winding drums simultaneously to pay out either cable and draw in the other cable to swing the boom in either direction, and means for engaging the paying out run of either cable to take up slack thereln,

3. In a dredge, a pivotally mounted boom,

sheaves thereon, a properly located fixed support, cables connected to said fixed support and running over the respective sheaves on said boom, winding drums connected to the other ends of the respective cables, means for operating said winding druinis simultaneously to pay out either cable and draw in the other cable to swing the boom in either direct-ion, and means for engaging the paying out run or bight of either cable to take up slack therein, and comprising a sheave mounted on said fixed support at a properly located point, and adapted to re ceive the said run or bight of the cable at a certain portion of its movement.

In testimony whereof, I have hereunto set my hand at Los ringeles, California this 5th day of December, 1913.

JOHN F. CRAIG;

In presence of ARTHUR P. KNIGHT, LORRAINE Domiow.

Copies of this patent may be obtained. for

five cents each, by addressing the Commissioner oi? Patents, Washington, D. c." 

